[lkjhgfdsa57]

> Given a URL for an HTTP resource, how do you know it does not contain child porn before you retrieve it?

As clueless404 stated, on the http web you don't automatically seed the content that you accidentally retrieved. On IPFS you're distributing it.

As an example, another posted here provided an IPFS link to resources, some of which are a copyright violation in some regions. In IPFS you can discover the nodes that are seeding it:

    $ ipfs dht findprovs ...contenthash...
    QmfWQHVazH6so9p27z27rr8TJSdBFGpH7hunDcaZ1EAQ2c
    ...

These are the node id's sharing the content. You can find all the IP addresses published by the nodes, including private ones:

    $ ipfs id ...nodehash...
    {
      ...,
      "Addresses" : [
        "/ip4/127.0.0.1/tcp/4001/ipfs/...hash...",
	"/ip4/192.168.1.5/tcp/4001/ipfs/...hash...",
	"/ip4/172.17.0.1/tcp/4001/ipfs/...hash...",
	"/ip4/1.2.3.4/tcp/4001/ipfs/...hash..."
      ],
      ...
    }

If your node accidentally retrieved a hash containing content that was illegal or otherwise bad your physical IP is easily discoverable.

A database of bad hashes is easily calculated given existing content using:

    $ ips add -n foo.mp4
    added ...hash... foo.mp4

This generates a hash for a file without uploading it to IPFS. You can then use findprov to see if anyone is sharing it.